diff --git a/modules/node/node.module b/modules/node/node.module
index 0a369675398..dd62af23b41 100644
--- a/modules/node/node.module
+++ b/modules/node/node.module
@@ -238,14 +238,20 @@ function node_teaser_js(&$form, &$form_state) {
 /**
  * Automatically generate a teaser for a node body.
  *
+ * If the end of the teaser is not indicated using the <!--break--> delimiter
+ * then we try to end it at a sensible place, such as the end of a paragraph,
+ * a line break, or the end of a sentence (in that order of preference).
+ *
  * @param $body
  *   The content for which a teaser will be generated.
  * @param $format
  *   The format of the content. If the content contains PHP code, we do not
- *   split it up to prevent parse errors.
+ *   split it up to prevent parse errors. If the line break filter is present
+ *   then we treat newlines embedded in $body as line breaks.
  * @param $size
  *   The desired character length of the teaser. If omitted, the default
- *   value will be used.
+ *   value will be used. Ignored if the special delimiter is present
+ *   in $body. 
  * @return
  *   The generated teaser.
  */
@@ -279,7 +285,7 @@ function node_teaser($body, $format = NULL, $size = NULL) {
   }
 
   // If we have a short body, the entire body is the teaser.
-  if (strlen($body) < $size) {
+  if (strlen($body) <= $size) {
     return $body;
   }
 
@@ -308,8 +314,14 @@ function node_teaser($body, $format = NULL, $size = NULL) {
   // A paragraph near the end of sliced teaser is most preferable.
   $break_points[] = array('</p>' => 0);
 
-  // Other line breaks often indicate a paragraph.
-  $break_points[] = array('<br />' => 6, '<br>' => 4, "\n" => 1);
+  // If no complete paragraph then treat line breaks as paragraphs.
+  $line_breaks = array('<br />' => 6, '<br>' => 4);
+  // Newline only indicates a line break if line break converter
+  // filter is present.
+  if (isset($filters['filter/1'])) {
+    $line_breaks["\n"] = 1;
+  }
+  $break_points[] = $line_breaks;
 
   // If the first paragraph is too long, split at the end of a sentence.
   $break_points[] = array('. ' => 1, '! ' => 1, '? ' => 1, '。' => 0, '؟ ' => 1);